Current-converting device.



A. R. BULLOCK.

CURRENT CONVERTING DEVICE.

APPLICATION FILED JULY 28,1913.

'1 ,216,41 3 Patented Feb. 20, 1917.

W217i 650'60'. 1 1111/6 jiforr JVIL'ZWQQOR Q m4 UNITED STATES PATENTOFFICE.

ARTHUR B. BULLOCK, OF CLEVELAND, OHIO.

CURRENT-CONVERTING DEVICE.

Application filed July 28, 1913.

To all whom it may concern:

Be it known that I, ARTHUR R. BULLOCK, a citizen of the United States,residing at Cleveland, in the county of Guyahoga and State of Ohio, haveinvented a certain new and useful Improvement in Current-ConvertingDevices, of which the following is a full, clear, and exact description.

This invention relates to a current converting device for changingalternating current to direct current and vice versa, and moreparticularly to the type of such devices which employ a rotatable bodyof segments.

The object of the invention is to provide such a device wherein thecurrent being con verted will be cut off simultaneously witlr thebreaking of the circuit through the seg ments.

Generally speaking, the invention comprises the elements andcombinations thereof set forth in the accompanying claims.

Reference should be had to the accompanying drawing forming a part ofthis specification in which Figure 1 is a top plan view of one form ofmy device; Fig. 2 shows in section the rotating parts, anddiagrammatically the electrical connection; Fig. 3 is a top plan view ofa modified form of the device; Fig. 4 is a diagrammatic illustrationshowing the rotating portions of the device and the manner of theirelectrical connection; Fig. 5 is a perspective View of a modified formof my device, and Fig. 6 is a development of the surface of the rotatingbody shown in Fig. 5.

The machine herein shown is of the commutator type which employs arotating body provided with segments which are grouped, to which currentis fed and from which current is taken, in such a manner that the sidesof the alternating current circuit and the direct current circuit areconnected with each other in alternation.

Tn devices of this type, more particularly those for converting analternating to a direct current, at the time a brush bearing upon thesegmented body, passes from a live segment to a portion of the segmentedbody which is electrically dead, and again to a live portion of thebody, there is a tendency for the current to flash over from a livespace to an adjacent live space, which flashing Over y P931 in an ar t mquite destructive,

Specification of Letters Patent.

Patented Feb. 20,1917.

Serial No. 781,510.

The possibility of such an occurrence is a weak feature of such amachine, and the purpose of the herein disclosed device is to remove asmuch as may be the possibility of such occurrences.

In the construction of devices herein em ployed, the current beingsupplied over the feeding-in ring, is broken at the same time that thecurrent breaks upon the segmented body of the converting device. Thisbreaks the current at two places in series. In this way, the tendency toflash over is minimized and very largely eliminated.

Referring to Fig. 5 of the drawing, 1 and 2 are standards for suportinga shaft 3. Upon the shaft is a rotating body 4, upon the periphery ofwhich are a plurality of conducting elements which are shown in Fig. 6,and are represented by the segments 5, 6, 7 and 8. Each of the segmentsis con: nected with a portion of a conducting strip. The segment 5 isconnected with the portion 9.

The segment 6 is connected with the portion 11 and the segment 8 with aportion 12 of a corresponding strip upon the opposite side of therotatable body.

The spaces in between the segments and between the sections of the ringsare filled with some non-conducting material.

Between the portions 11 and 12 is a conducting strip 12", and betweenportions 12 and 11 is a conducting strip 11. Similarly portions 10 and 9are separated by a strip 10", and portions 9 and 10 are separated by astrip 9 These various strips are separated by insulated, electricallydead spaces, indicated at 11 11, 12 9", 9 and 10 The insulated spacesare wider than the brushes passing over them.

The conducting strips 11, 11 12 and 12 are all electrically connectedand the conducting strips 9, 9", 10 and 10", are also electricallyconnected as indicated at 18 in Figs. 5 and 6. These in effect formcollector elements. for they may either conduct current to or from thesegments, 5, 6, 7 and 8.

A brush 13 is adapted to engage with the strips 9, 9", 10, and 10 whilethe brush 14- is adapted to engage with the segments 11, 11 and 12 12.These brushes are, as shown, connected with a source of alternatingcurrent.

Brushes 15 and 16 are placed so as to engage with the segments 5, 6, 7and 8, and are so spaced that the brushes will simultaneously engagewith segments, which extend toward opposite sides of the body 4:, and tothe strips of the collector elements. These brushes are connected withthe circuit which carries the rectified direct current.

It will be apparent by reference to Fig. 5 that brushes 13 and 15, aswell as brushes 14: and 16, will pass on to non-conducting portions ofthe rotating body 4; simultaneously, and it is the aim to have them sodo. fore the A C circuit is broken simultaneously with the D G circuitbetween the segments and the brushes 15 and 16. Thus any arc tending toform, due to the breaking of the circuit through the segments, willupon. each side of the circuit be divided between two points of break,and thisgreatly reduces the are at both places of break.

For the purpose of operating the device, a synchronous motor will beemployed to rotate the shaft 3. In this manner the rotation of the body1 will. be in synchronism with the phase reversals of the alternatingcurrent. No particular type of synchronous motor is here disclosed forany synchronous motor which runs with suflicient precision, may be used.

In Fig. 1 there is shown a shaft which is mounted in bearings 21 and 22.Upon the shaft is a segmented body 23 which as shown in Fig. 4 isprovided with four conducting portions, indicated respectively at 25,26, 27 and 28. The conducting portions 25, 26, 27 and 28 are shown assegmented merely because it is most feasible to make a rotating body ofsegments, such as herein employed, according to usual commutatorconstruction. However, these conducting portions may each be of a singleunitary conducting material. The portions 25 and 26 are electricallyconnected, as are the portions 27 and 28.

Upon the shaft 20, there are likewise two annular conducting portionswhich are indicated at 29 and 30. In the present construction, theseform collector elements. These conducting portions 29 and 30 are dividedinto strips which are separated by insulating portions 31, and themembers 29 and 30 are separated from each other by a non-conductingportion 32.

In Fig. 2 we may assume that the conducting body shown is the conductingportion 30, and as will be seen, the same is divided into severalsegments which are connected with each other by means of suitableconductors, as indicated at 33. The conducting portion. 30 is shown asconnected with the segments 25 and 26, while the conducting ring 29 iselectrically connected with the segments 27 and 28. The segments of eachof the conducting portions are electrically connected Thereand formsingle conducting portions or segments.

Brushes 3% and bear upon the conducting elements 29 and 30 respectively,while brushes 3G and 37 engage with the segments 25, 2b, 27 and 28, asthese segments are ro tating. The brushes which have just been mentionedare carried upon suitable supports which are generally indicated at 38and As will be noted in Fig. 2, assumin the direction of rotation of thebodies to be as indicated by the arrows, that the brushes 36 and 37 havejust passed from conducting portions 28 and 25 respectively, and uponthe drawing are shown, as in contact with the insulated spaces which areadjacent these conducting portions. The brush $35 is also seen to be onan insulated portion between, :uljacent segments of the romlurtiug strip36, and the brush Bl, although not shown in the drawin, is likewise uponan insulated portion which is between adjzurent portions of theconducting strip 29.

The arrangement of the brushes 3t, 35. C36 and 37 should be such thatthe l) (l circuit is ln'oken simultaneously with the A C circuit.

lVith such an arrangement, it is apparent that there could be noflashing over between contiguous conducting portions upon the rotatablebody 23, for the flashing over would only take place as the brushes 37and 36 were passing from conducting portions upon this body 23. If atthis time, the supply of current is also broken, it will be quite c earthat there would be no flaslrover, be cause of the fact that the supplycurrent is not flowing.

The principle of construction which has just been described may beemployed in 7 connection with the current converting device which isshown in my pending application, Serial No. 633,027, filed June 14th,1911.

In Figs. 3 and 4, herein, I have indicated. the manner in which theprinciple herein disclosed could be applied to the device shown in saidapplication 633,027.

In Fig. 3 there is a shaft 40 which is mounted in bearings ll and Uponthe shaft are two conducting portions 1 3 and 44. made up of stripswhich are separated by insulated portions. the same as indicated in Fig.The conducting portions are electrically connected. as indicated at inFig. 4t. These portions 43 and l-lform collector elements.

There is also a rotatable segmented body carried by this shaft, which isindicated at d6. As shown in. Fig. -'l, this body is provided withconducting portions or segments 41-7. 48, a9 and 50, the portions 4L7and 4-8 being electrically connected, as are also the portions 19 and50. tions 5% may be electrically connected with he l The conductinguerthe portions 47 and 48 upon the rotatable body 46, and the segmentsof conducting portions 43, may be electrically connected with conductingportions 49 and 50 of the rotatable body 46.

There is a third rotatable body, indicated at 51, which is provided withconducting portions or segments 52, 53, 54 and i he conducting portions52 and 53 are electrically connected with each other and also with theconducting portions 47 and 48 upon the body 46. The conducting portions04 and are also electrically connected with each other, and with theconducting portions 49 and 50 upon the body 46.

The conducting portions 52, 53, 54 and 55 are however, of not so greatwidth as the conducting portions upon the body 46, it being the purposeof the construction to have great carrying capacity upon the body 46,whereas the conducting portions upon the body 51 will be utilized nearlyat the time ot breaking of the circuit.

Cooperating with the conducting portions 43 and 44 are brushes 5G and.57, these brushes being connected with the source of supply ofalternating current. Upon the rotating body 44 are brushes 58 and 59,these brushes being connected with the external D C circuit. Upon therotatable body 51 are brushes and G1 which brushes are also connectedwith the D C circuit.

The conducting portions and their corresponding brushes of the rotatablebody 51 are arranged with respect to the conducting portions of the body46 and their brushes, such that the brushes 58 and 59 will have passedonto insulated portions of the body 46 a little in advance of thepassage of the brushes 60 and 61, onto insulated portions of the body51. In this way, the breaking of the D C circuit is accomplished upon arotatable body which is distinct from the body which carries thecurrent, thus providing space between the point at which the D C circuitis broken, and the body on which it is carried, and by so muchminimizing the likelihood of arcs forming.

, The brushe 56 and 57 are so arranged with respect to the conductingportions 43 and 44, that the brushes 56 and 57 will pass upon insulatedportions simultaneously with the passing of the brushes 60 and 61 toinsulating portions.

Inasmuch as the shaft 40 will be operated by a synchronous motor, whenthe deice is used as a rectifier, it will be apparent that the breakingof the circuit by the brushes 60 and 61 takes place at a time when boththe alternating current voltage and current waves are subs antially atZero.

It therefore follows that the conditions at the time of break of thecircuits is such as to practically preclude any flash over or arcingbetween adjacent segments.

It is perfectly within the province of my invention to break each sideof the circuit in more than two places if desirable, and thus divide anypossible arc, which may form at the points of breaking the circuit, toany group of conducting elements with another circuit, the electricallycooperating conducting elements in each group being connected, both ofthe above mentioned means for connecting the said conducting elementswith the said circuits being arranged to substantially simultaneouslybreak the circuits through the said conducting elements.

2. In a current converting device, the combination with a group ofinsulated conducting elements, brushes bearing upon said elementswhereby the elements are connected with a circuit, a second group ofinsulated conducting elements, a set of brushes bearing upon said secondset of conducting elements by which said elements are connected with asecond circuit, the electrically cooperating conducting elements of thetwo groups being electrically connected, the brushes being arranged tosubstantially simultaneously break the circuits through the saidconducting elements.

3. In a current converting device, the combination with a plurality ofcollector elements, each collector element being formed with a pluralityof strips which are insulated from each other, the strips of eachcollector element being electrically connected with the other strips ofits particular collector element, a group of insulated conductingsegments being electrically connected, means for electrically connectingthe collector elements with a circuit, means for electrically connectingthe conducting segments with a second circuit, both of said means beingarranged to substantially simultaneously break the circuits through thecollector elements and the groups of the conducting segments.

4. In a current converting device, the combination with a plurality ofcollector elements, each collector element comprising a 7lurality ofconducting strips which are insulated from each other, a group ofinsulated conducting segments electrically cooperating, the segments andcollector elements being electrically connected, brushes bearing uponthe collector elements and connected with a circuit, other brusheshearing upon the conducting segments and connected with a secondcircuit, the brushes being arranged to substantially simultaneouslybreak the circuits through the strips and segments.

5. In a current converting device, the combination with a plurality ofcollector ele ments, each of said elements comprising a plurality ofinsulated conducting strips arranged in annular alinement, the strips ineach collector element being electrically connected, a plurality of setsof conducting segments, the conducting segments in each set beingdirectly electrically connected with electrically cooperating segmentsin other sets, said segments also being electrically connected withelectrically coop erating strips of the collector elements, brushescooperat ing with the said collector elements, and brushes cooperatingwith each of the other sets of segments, the brushes in one set beingarranged to remain in Contact with its segments, when the brushes uponthe other set of segments have ceased to contact with said segments, thebrushes upon the lirst set of segments and the brushes upon thecollector elements being arranged to disengage with the strips andsegments substantially simultaneously.

6. In a current converting device, the com bination with a pair ofannular collector elements, each of said elements comprising a pluralityof strips arranged in annular alinement which are electricallyinsulated, a plurality of annularly disposed conducting segments,cooperating segments being directly electrically connected with the saidstrips, brushes bearing upon the strips and upon the segments, saidbrushes being arranged to disengage with the segments and the stripssubstantially simultaneously.

7. In a current converting machine, the combination with a shaft, a pairof collector elements upon said shaft, each or said ele ments comprisinga plurality of insulated conducting strips which are arranged in annularalinement, brushes bearing upon said strips, an annular body mountedupon said shaft, said body being provided with conducting portions whichare separated by non-eondncting portions, the said condiuzting portionsupon the annular body being directly connected with the said conductingstrips with which they electrically cooperate, brushes bearing upon thesaid annular body, the brushes upon the collector elements and the saidbody being arranged to disengage with the strips and segmentssimultaneously.

In testimony whereof, I hereunto a llix my signature in the presence oftwo witnesses.

ARTH UR ll. BULLO (1K. lVitnesses A. J. Hunsow, L. I. Pon'rnu.

Copies of this patent may be obtained. for five cents each, byaddressing the Commissioner of Patents, Washington, D. 0.

